> ---- > class Bla { > @Property Bla self = this > } > println new Bla() > ---- > throws NPE. It's probably helpful to say that it causes an NPE in the compiler: Caught: java.lang.NullPointerException java.lang.NullPointerException at org.codehaus.groovy.ast.ClassNode.equals(ClassNode.java:540) at org.codehaus.groovy.ast.ClassNode.equals(ClassNode.java:538) at org.codehaus.groovy.classgen.AsmClassGenerator.doConvertAndCast (AsmClassGenerator.java:993) at org.codehaus.groovy.classgen.AsmClassGenerator.visitCastExpression (AsmClassGenerator.java:1429) at org.codehaus.groovy.classgen.AsmClassGenerator.evaluateEqual (AsmClassGenerator.java:2812) at org.codehaus.groovy.classgen.AsmClassGenerator.visitBinaryExpression (AsmClassGenerator.java:1055) at org.codehaus.groovy.ast.expr.BinaryExpression.visit (BinaryExpression.java:79) at org.codehaus.groovy.classgen.AsmClassGenerator.visitAndAutoboxBoolean (AsmClassGenerator.java:2876) at org.codehaus.groovy.classgen.AsmClassGenerator.visitExpressionStatement( AsmClassGenerator.java:1021) at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit (ExpressionStatement.java:70) at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement (CodeVisitorSupport.java:165) at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement (ClassCodeVisitorSupport.java:93) at org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement (AsmClassGenerator.java:465) at org.codehaus.groovy.ast.stmt.BlockStatement.visit (BlockStatement.java:82)